민무늬근 is a type of muscle tissue found in the human body. It is characterized by its non-striated appearance, meaning it does not have the striped pattern seen in 골격근 (skeletal muscle). This type of muscle is involuntary, meaning it operates without conscious control, and is primarily found in the walls of internal organs such as the stomach and intestines. The main function of 민무늬근 is to facilitate the movement of substances through these organs. For example, it helps in the process of digestion by contracting and relaxing to push food along the digestive tract. This muscle type plays a crucial role in maintaining various bodily functions, including circulation and digestion.